


Side Effects Knot Listed

by LeoArcana



Category: Supernatural
Genre: Accidental Knotting, Alpha!Dean, Bottom Castiel, Breeding, Dog Dean, Episode: s09e05 Dog Dean Afternoon, Knotting, M/M, Masturbation, Plot What Plot/Porn Without Plot, Rimming, Shameless Smut, Smut, Top Dean, how do you tag smut, kind of
Language: English
Status: Completed
Published: 2014-05-30
Updated: 2014-05-30
Packaged: 2018-01-27 14:24:37
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,639
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1713833
Author URL: https://archiveofourown.org/users/LeoArcana/pseuds/LeoArcana
Summary: <blockquote class="userstuff">
              <p>The potion.  It had bonded him with a dog.  It made him act and think like a dog.  Physics weren’t too far out of the question, but the potion had worn off hours ago…right?</p>
            </blockquote>





	Side Effects Knot Listed

The day had started out perfectly normal.  The animal-communications potion had worn off, right before Dean had learned the real reason for dogs’ companionship, much to his annoyance.  They’d come straight back to the bunker, arriving sometime around noon.  Dean felt oddly dirty after breaking the animal connection and wanted nothing more than to scrub the feeling away.  Sam rolled his eyes at his brother as he’d stalked away to his room to shower.  Dean shut his door behind himself, doing the same unnecessarily with the door of the bathroom attached to his room, and stripped down.  The bunker may be old, but it took no time for the water to heat up.  He stepped in under the hot spray and immediately took to scrubbing shampoo through his hair, lathering soap across his skin and rinsing it all off before doing it once more because the connection had left him feeling that weird.

With the second round of soap disappearing down the drain, Dean let out sigh of relief and leaned back against the shower tiles and slid down to the floor.  He enjoyed the hot water for no more than a minute before a twinge of heat crawled through his lower stomach, calling attention to something he’d neglected over the past couple days.  Dean closed his eyes with a halfhearted, lazy grin and let a hand slide across the water smooth skin of his stomach.  He traced his fingers around his stomach a few times before dragging them further down and taking hold of his dick in a loose grip.  He had plenty of time; there were no new hunts or leads to push him into getting off quickly, but he was a little tired.

Dean stroked himself a few times, letting a soft, content hum escape his mouth as his felt himself hardening in his hand.  He tightened his grip, just barely, but kept a slow and determined pace.  The fingers of his left hand skimmed over the skin of his hip, trailing them down along the line between his thigh and abdomen, going just a little lower than the other hand a softly caressing his nails over his sac.  He shivered at the sensation, tipping his head back and biting his lip.  Still keeping his pace, he curled his fingers around his sac and gently rubbed his thumb over both his balls.  That had prompted him to speed up, swiping his thumb over the head of his dick and smearing the beaded precome down his length with the water. 

Dean let his jaw fall slack as breathy pants began to escape him.  He stroked faster, fisting into his hand and moving his left ring finger to press against his perineum; eliciting a high pitched whine he barely managed to choke off.  He stretched out, as much as the shower would allow, and started thrusting up into his hand, loving the way his water and precome slicked hand glided and twisted around his dick; the way his fingers started coming away from each other near the base and back together at the head.  There was a tiny voice in the back of his head that said something was wrong, but it was drowned out by the ecstasy.  It wasn’t until he couldn’t even touch his middle finger to his thumb around his dick that that voice in his head was acknowledged.

He dipped his head forward, breathing hard and ragged at this point, and forced himself to open his eyes.  The sight of his swelling dick shocked him hard enough to make him come with a strangled cry as his orgasm was punched out of him.  Thick ropes of cum spilled across the tiled floor and the sides of his knees, washed away by the shower only to be replaced by another wave.  Dean curled his toes, biting his lip harder than before as the second wave came just as strong.  As did the third and fourth, earning a pained and over-pleasured cry from the hunter.  The fifth and sixth wave came weakly, closer to normal, and the seventh was barely there at all.  Relieved whines and whimpers spilled from Dean’s mouth as he tentatively let go of himself with shaking hands.  He hadn’t realized he’d shut his eyes again, but when he opened them, he was greeted by the same sight.  His swollen dick looking like someone had shoved a tennis ball in his shaft.

 He stared down at himself with a mixture of horror and confusion, his entire body now quaking.  Dean hesitantly wrapped his fingers around the mass, whining at the painful pleasure the pressure brought.  This was wrong.  Dean fumbled around in the shower, swiping at the faucet and shutting off the shower and pushing himself up on shaky legs.  He hardly wasted more than a few seconds drying off before wrapping the towel around his waist and throwing the bathroom door open, making a beeline for his laptop, sitting on his bed where he’d left it.

He flipped it open, logging on and pulling up the search engine faster than he could ever remember doing.  Trembling fingers hovered over the keys, what was he supposed to search exactly?  Dean scowled and shook his head, he didn’t care what he searched as long as he got an answer.  One that wasn’t spontaneous and extremely malignant cancer.  He decided to be direct and type in the exact situation.  He was given a list of forums of other people posting similar questions; good, it wasn’t just him.  Most of them had been given the same answer and Dean immediately researched it.  He had none of the other symptoms.  At all.  In fact, the more he read into it, the more he realized this was not his situation; it was just him. 

Panic began to rise in him and he clicked back to the search engine, casting a nervous glance down at his swollen dick.  He rephrased the search and blanched at the result.  It was nothing disgusting or gross, but it wasn’t…human.  The rephrased search had given him results related to dog breeding.  Dean shook his head in disbelief.  Why the hell did it give him dog related results?  And more importantly, why the _fuck_ was it so accu—

The potion.

It had bonded him with a dog.  It made him act and think like a dog.  Physics weren’t too far out of the question, but the potion had worn off hours ago…right?  Dean withdrew from the laptop, feeling his heart drop and leaned back against his pillows.  He could smell everything in his room, _everything_.  Everything he saw was a sharper image.  He could hear the faint, distant sounds of Sam typing away on his own laptop in his room just across the hall and one door down.  The potion hadn’t worn off.  He’d simply lost the communication aspect of it.

Dean reached forward and slapped the laptop shut, picking it up and basically dropping it onto the night stand before leaning back again and running his hands down his face.  He hadn’t read much about…knots, _fuck,_ he had a _knot_ , but he had caught a few glimpses of the results’ information.  It was natural, in _dogs_ , not humans, and it would go away.  The amount of time it took to go away ranged from just a couple minutes to upwards of an hour, depending on the dog.  Given his luck, he’d probably wind up on the hour end of the spectrum.  There was nothing he could do, nothing he wanted to do except curl up and hide.  And he did just that, kicking the blankets back and squirming under them, holding his towel to his waist as he did.  He curled up under the blankets, mindful of his knot, pulling the sheets up to his head and burying half his face into the pillow.

It didn’t take long for him to fall asleep, the force of his orgasm had left him completely drained.  His sudden panic had been the only thing stopping him from passing out in the shower.  He slept for nearly six hours before the banging at his door woke him up.  He mind was still groggy and slow to realize it was Sam yelling something about going out to dinner and if Dean wanted anything.

“I don’t care,” Dean grumbled loudly, “Whatever’s fine.”

“I’m gonna bring you a salad then,” Sam teased.

“God, no,” Dean groaned, “Whatever that isn’t that is fine…and pie.”

“You and pie, I swear to god…”

Dean waited until he could no longer hear Sam’s footsteps moving down the hallway before sitting up in bed.  He took a steadying breath and pushed the covers back, looking down at himself.  Everything was back to normal.  _Thank fuck._   Dean got out bed, finally ditching the towel and getting dressed before exiting his room.  Sam had left, but he could hear someone in the study.  Instinctively, he knew it was Kevin and he was quickly making his way to the study.  Kevin had been the one to research and provide the potion, maybe he could tell Dean a little more about it.  Nothing personal, no way in hell was he going to mention this incident, but maybe something useful along the lines of its potency or how long it lasts.

“Hey, Kev,” Dean called.

Kevin looked up from whatever book he was pouring over and slid it away a little.

“What’s up?” Kevin asked.

“That potion we had you find, the one for talking to animals…”

“Yeah, that was weird.  And you guys do a lot of weird things.”

Dean huffed and rolled his eyes.

“What’d you wanna know about it?”

“Did the book, or wherever you found it, say anything about how strong it was?”

“I don’t think it did…Why, are you still under it or something?”

“Take a guess.”

“Alright, I’ll go look for it again and see if it says anything,” Kevin sighed.

Dean gave him an unintentionally spiteful smile as he got up and started off towards the library.  Dean clenched and unclenched his jaw a few times, trying to stay calm, and started pacing around the study for a few minutes.  When he decided Kevin was taking too long, he turned on his heels and strode down the library.  He came around the corner of a shelf of books and ran into Kevin, making him drop the book he had in his hands.  Kevin rolled his eyes and picked it up off the floor.

“Find anything?” Dean pressed.

“Well, I did and I gotta find it again,” Kevin grumbled.

Dean watched him anxiously as he thumbed through the pages.  Kevin paused for a moment, confused and slightly put off by Dean’s proximity.  Picking up the hint, Dean took a half step back.

“So it says that it depends mostly on the person—“

“That doesn’t help.”

Kevin gave him a tired glare.

“For some people it’s a lot more potent, lasts longer with heavier side effects.  Other people, not so much,” Kevin shrugged, “Basically you’re just gonna have to wait it out.”

“Does it say how long the longest one lasted?”

“This is book about spells, not records,” Kevin deadpanned.

“Is there a records book?” Dean snipped.

“Dunno, you’ll have to look.  Just wait it out, it’s not permanent,” Kevin replied, “I’m gonna go keep working on the tablet.”

Kevin handed the book off to Dean and walked past him.  Dean clicked his tongue, dropping the book on the nearest shelf and stalking down to where the records were stored in front of their dungeon.  He wasn’t sure where to start looking, some boxes were labeled and some weren’t.  So, he just started grabbing boxes off shelves and rifling through them.  After about three boxes, Dean distantly heard Sam calling for him.  Dean only gave a half-hearted shout in response and didn’t even bother looking up when Sam walked in with dinner.

“They didn’t have any pie—“

“Story of my life…” Dean mumbled.

“But they had a bacon cheeseburger, so here.”

Sam pulled a paper wrapped burger out of the bag and set it beside the box Dean was currently digging through.

“What’re you looking for?” Sam asked.

“Nothin’, just, uh…few records about that dog potion.”

“Still bothering you?” Sam grinned.

“Shut up.”

“Maybe a game of fetch’ll cheer you up?” Sam laughed.

Dean fixed him with a side-eyed glare.  Maybe if the concoction wasn’t messing with his physiology, he’d laugh or crack some retort.  Sam held up his hands in apology and turned to leave him to his searching.  Dean finished going through the box and started in on the next, absent mindedly eating his burger.  The box following that one finally held some useful information.  He pulled out a folder containing records of all the Men of Letters who had used it; all six of them.  He flipped through the pages, noting how much of the potion they’d taken and how long it had lasted.  The shortest and smallest dose had last two days and provided only basic communication.  The heaviest dose had lasted a month and had the taker just short of fur with ears and a tail.  He dropped the files sitting back in the box and sat back, burying his hands in his face.  They hadn’t even bothered measuring how much to take, Dean just downed the whole thing.

He pushed the box away, standing and slinking off to his room, avoiding Sam and Kevin as he went.  Reaching his room, he flopped onto his bed on his stomach.  Like Kevin said, he’d just have to wait it out.  Best case scenario, he’d be fine tomorrow.  Worst case, a month.  Dean let an almost audible whine escape at the thought of a month. 

               

Nearly every day, Dean got off in the shower right after waking up and again before going to sleep; sometimes in between if he had time to hide out until his knot went away.  Partially because that was really the only way to see if he was back to normal, and also because he felt like he just _needed_.  He wanted to go out, sweet talk some girl and bring her to hotel, but then what?  How was he going to explain _any_ of what happened?  Until this knot went away for good, he couldn’t do anything.

It’d been a week and a half and he was at his wit’s end.  Dean had no idea how the hell the one MoL had survived a month.  Sam and Kevin couldn’t stand his behavior anymore; he’d been too snappish and short-tempered.  He even bordered on growling at them a few times.  That had been the last straw.  They’d all but pushed him out of the bunker and told him not to come back until he did whatever he needed to do. 

Dean grumbled to himself as he drove around town.  He might not be able to wine and dine a pretty girl, but he could still go out and get himself a good, hard drink.  That’s how he found himself in a bar five miles outside of Lebanon.  Two drinks had taken the edge off, but the flirtatious women had brought it right back.  By his third drink, Dean was nearly ready to bite the hand that tapped him on the shoulder.

“ _What do y—_ Cas?”

“Hello, Dean.”

“What’re you…the hell are you doing here?” Dean asked.

“Sam and Kevin called me, they said you were in a foul mood.”

“How did…?”

“They gave me the GPS coordinates from your phone,” Cas answered, “Mine is still functioning.  For the moment.  I need to find a charger for it, however.”

Dean shifted over a little to allow Cas to take the seat of the barstool next to him.  Dean sighed, rubbing his thumb up and down the neck of his beer bottle.

“Listen, Cas, about what I said—“

“You’re reasons are your own.  If you don’t feel you should explain them, then I do not expect you to,” Cas replied.

If Cas had meant that to be comforting, he’d failed at that.  Dean tapped the bottom of the beer against the counter a few times before taking a drink.  He finished off the beer and waved at the bartender for two this time; one for Cas.  The silence between them had been tense, but was quickly beginning to ease.  Until Dean began to notice the number of eyes on them.  He gritted his teeth, shifting closer to Cas and shooting a few warning looks.  Most of them were discouraged, but when Dean saw a redhead approaching with eyes on Cas, he bristled.

“Hey, how’s it goin’?” she smiled.

“Well, thank you,” Cas replied, “Yourself?”

“It’s fine, better if I wasn’t going back to an empty apartment, y’know?”

Dean tightened his grip on the bottle.

“I’m sure you could find a roommate to share,” Cas suggested.

Dean quirked a smile at that.

“Yeah, I probably could.  Maybe someone who—“

“You didn’t pick up at a bar?” Dean cut.

The redhead looked taken aback, glancing between Dean and Cas.

“Um, I’m sorry,” Cas apologized, “He’s been…temperamental as of late.”

Dean narrowed his eyes at Cas, then looked up at the woman with a sneering smile.

“Oh, a-are you two…?”

“Yeah,” Dean snapped, “He’s with me.”

“I’m sorry, I didn’t realize you were together,” the woman apologized, sounding sincere, “I never would’ve…”

She trailed off at seeing Dean move protectively closer to Cas.  She worked her mouth a few times before nodding and leaving them alone again.  Cas tilted his head in confusion and turned to face Dean, only slightly phased by the hunter’s closeness.

“Dean, I thought you valued personal space,” Cas said.

Dean shook his head, clearing his mind a little and leaned back.

“…Dean?”

“What?”

“Did…she imply she thought we were in a relationship and…you promoted the thought?” Cas asked.

“I’m not drunk enough for this,” Dean muttered.

“I would rather you not be drunk.”

Dean eyed him suspiciously before taking another drink.

“Do you intend to just stare at me for the rest of the night?”

Dean sputtered his drink, wiping his mouth his sleeve and stared at Cas incredulously.  Cas, to his credit, kept a perfectly calm face and waited for a response.  The idea of what Cas was suggesting immediately shock of interest straight down to his dick.  He chewed on his lip; he couldn’t do that with Cas.  Not while he had this problem, at least.  Sure, Cas probably wouldn’t find it as weird or strangely frightening, but things would still be downright awkward and they wouldn’t be able to do anything about it for an hour.

“Dean.”

Dean snapped his head back up.

“Well?”

“Uh, y-yeah, we should leave.”

He wasn’t sure why he was agreeing to this.  Yes, he wanted to.  But he’d _just_ reminded himself of why he couldn’t.  Still, he found himself following Cas out of the bar, feeling warm beneath all his layers.  Dean threw open the door of the Impala, nearly trembling with need.  Cas slid into the passenger seat and glanced at him curiously.

“There’s a motel about a mile up the road,” Cas commented.

Right, motel.  The bunker was too far away, plus Sam and Kevin were there.  The Impala would be too cramped.  Dean switched the ignition, throwing it in gear and tore out of the parking lot, earning a surprised expression that flashed across Cas’ face.

It took Dean just under a minute, literally, to reach the motel.  It was a little classier than what he and Sam tended to stay, not by much though.  He hardly even paid attention to its looks as he hastily paid for a room, then going back out to the car to get Cas and hurry him towards their room.  Dean could feel his mind beginning to unravel with every step he took.  If he’d been any weaker, Cas would probably be against a wall right now.

He swung the door open, letting Cas through, and practically slammed it behind himself.  The moment Cas turned around, Dean was on him.  He wrapped his arms around the former angel’s waist, touching their foreheads briefing before roughly crashing their lips together.  The tiny voice in the back of Dean’s mind screamed for him to back out while he still could, but he was still kissing Cas so roughly and desperately that he was forcing him back towards the bed.  Cas broke them apart, gasping for breath just as the back of his knees made contact with the bed’s edge.  Between bumping the bed and Dean’s insistence, he fell backwards and dragged Dean down with him.

Dean pulled his arms back from him them, getting up to a low crouch over him and began nipping at Cas’ mouth and jaw.  Cas squirmed further up the bed, followed very closely by Dean, to get a more comfortable spot on the bed.  Dean’s lip twitched in annoyance as his moving and he dropped lower, pinning Cas where he was.  He relented on his nips and kisses, panting against Cas’ neck as he ground his hips down on Cas’.  He was rewarded with a stifled moan and fingers digging into his arms.

“ _Mine_ ,” Dean growled.

Dean scrambled at the hem of Cas’ shirt, grabbing hold of it and ripping it over Cas’ head. 

“Dean, slow d—“

“No,” Dean grumbled.

Dean lifted himself just enough to start fumbling at his own layers, his hands shaking with anticipation.  Cas grabbed his wrists, receiving a frustrated glare, and pushed the hunter’s hands away.  He made short work of the buttons on Dean’s shirt and peeled it back over his shoulders.  Dean gave a predatory grin and resumed his deep kissing as his hands trailed down the Cas’ belt, undoing it and ripping it away in heartbeat.  He couldn’t get their pants off fast enough, snarling into Cas’ mouth as he pulled the pants off the former angel and shoved his own down.  Both of them let out a ragged breath as the cool air rushed over their bare skin.

Dean’s teeth and tongue quickly trailed down Cas’ chest and stomach, hardly stopping to tease him.  He nuzzled at the base of Cas’ dick and licked a strip up, swiping away the slowly gathering precome.  He flashed a grin up at Cas before moving back up enough to grab him by the shoulders and turn him over.  Cas made a noise of annoyance at being man-handled, but Dean brushed it off as he moved back down.  Cas wrapped his arms around a pillow and buried his face in it when he felt Dean’s breath on his ass.  A whine followed a second later when his tongue circled his entrance.

“Relax…” Dean murmured.

He tried to do as Dean said when his tongue pressed past his rim.  Cas squirmed and shifted, pushing back against Dean and pulling away.  Dean growled in annoyance at him and pinned his hips down while he continued licking him out.

“ _Dean_ …” Cas whined.

He felt a puff of breath over his hole, made colder by Dean’s work.

“Can’t wait, can you?” Dean mumbled.

The bed shifted as Dean moved back up the bed, bringing his head up beside Cas’. 

“Can’t wait to be _bred_ , huh?”

“’Bred’…?” Cas repeated absently.

Dean’s tongue swiped over the shell of Cas’ ear as he rubbed his dick between Cas’ cheeks.

“That’s right, ‘m gonna breed you so full,” Dean grinned.

When the head of Dean’s dick pressed against Cas’ hole, Cas was pulled from his haze.  He was nowhere near ready.  Dean hadn’t prepped him enough and there was nothing to ease the way, save for Dean’s saliva.  Cas tried to twist over to face Dean, but Dean held him down by the wrists and used his hips to keep Cas’ pinned as well.

“Dean, please, just a min—“

“No,” Dean growled, “Been waiting too long for this.”

Thankfully, it was Dean’s fingers that breached him.  Cas arched his back slightly as the two fingers quickly scissored him open and kept him that way.  Then Dean’s dick slid in, stretching him open— _splitting_ him open as his fingers retreated.  He bottomed out and paused, panting heavily above him.  Cas was relieved for the stall, though it hadn’t been entirely for his benefit.  Dean was trying to stave off his knot and orgasm.  _Shit_.  Dean dropped his forehead against the base of Cas’ neck; that voice in the back of Dean’s mind was chanting ‘ _this is horrible idea’_ and ‘ _stop, back out_ ’ over and over.  But his body was burning with need at this point; there was no way those thoughts were going to be acknowledged.

With a grunt, Dean pulled out and pushed back in slowly.  Cas groaned, a mix of pain and pleasure, and buried his face further into the pillow.  Dean pulled back again and thrusted back in with more force, just barely grazing Cas’ prostate.  He grinned to himself and changed the angle of his next thrust, then hit Cas’ prostate dead on.  A loud moan, almost unaffected by the pillow, escaped Cas and he pushed back against Dean.  Dean grabbed onto his hips and pulled Cas back onto him with every thrust.

“Listen to you,” Dean grumbled, “Moaning like a bitch in heat.”

Cas couldn’t even form a coherent response as the hunter continued striking his prostate.

“And I’m gonna fuck you like one.  Gonna knot your ass and fill you up,” Dean panted.

Another whine came from Cas, turning into a groan as Dean began to feel bigger inside him.  Dean moaned at the feeling of Cas getting tighter around him and forced himself deeper on each thrust.  Cas bite the corner of the pillow, stifling a cry as he came hard across the sheets and clenched tighter around Dean’s dick.

“Feel that?  My knot?” Dean grumbled, “’t’s gonna keep you all stuffed up for at least an hour, keep you tied to me like a bitch.”

“Dean, please…” Cas whimpered.

His knot had swollen too big for him to pull out, leaving him to rut deeper into Cas’ ass before heat pooled in his lower abdomen.  He draped himself over Cas’ back, licking his shoulder and sinking his teeth in as he spilled into Cas.  Another orgasm was suddenly ripped from the former angel as wave after wave of hot cum was pumped into him.  Dean continued rutting into him until he was finally began to taper off and he just layed still over Cas; locked inside of Cas.

His body trembled with the force of his orgasm and the dawning realization of what happened.  Every little movement he made seemed to cause him to come more into Cas.  Panic and fear at the situation began to well up inside him as he worked his mouth in search of an excuse or reason or apology.  The latter seemed to be easier to work with.

“Cas, I— I didn’t…I’m sorry, I—“

“Dean,” Cas spoke evenly.

Dean shut his mouth, swallowing a whimper as another, albeit weak, orgasm spilled out of him.

“Sam and Kevin informed me of the potion you took,” Cas started, “I knew of its potential side effects, I simply did not know how affected you were.”

“So, you knew I would— could…knot you?” Dean forced out.

“I was aware of the possibility, yes.”

“You…you _kinky fucker,_ ” Dean mumbled.

Cas hummed in amusement as Dean wrapped his arms around Cas’ chest.  He nuzzled at Cas’ neck, lazily licking and kissing it.

“I would be willing to help you through the duration of the potion’s influence,” Cas offered.

“Can’t think of anything better,” Dean murmured.

“So long as you clean up after yourself in between,” Cas added.

“You really are kinky…”

**Author's Note:**

> what i'm still doing this what


End file.
